What happened October 1950AD in Korea

In 19 October 1950, Mao made the decision to send the People's Volunteer Army (PVA), a special unit of the People's Liberation Army, into the Korean war and fight as well as to reinforce the armed forces of North Korea, the Korean People's Army, which had been in full retreat. Historical records showed that Mao directed the PVA campaigns to the minutest details.